Methods for transmitting and receiving control channel, base station, and user equipment

ABSTRACT

Embodiments of the present invention provide methods for transmitting and receiving a control channel, a base station, and a user equipment, which relate to the communication field, and can solve a transmission problem of available changing transmission resources caused by introduction of an E-PDCCH. A method for configuring a control channel resource includes: determining, by a base station according to a system configuration and/or user configuration, resource elements REs included in an extended control channel element E-CCE, and transmitting an extended physical downlink control channel E-PDCCH to a user equipment, where the E-PDCCH is carried by the E-CCE; and receiving, by the user equipment, the E-PDCCH, and obtaining the REs included in the E-CCE, and receiving, over the REs included in the E-CCE, the E-PDCCH transmitted by the base station. The embodiments of the present invention are used for configuring and detecting a control channel resource.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No.14/326,644, filed on Jul. 9, 2014, which a continuation of InternationalApplication No. PCT/CN2013/070252, filed on Jan. 9, 2013. TheInternational Application claims priority to Chinese Patent ApplicationNo. 201210004650.4, filed on Jan. 9, 2012. The afore-mentioned patentapplications are hereby incorporated by reference in their entireties.

TECHNICAL FIELD

The present invention relates to the communication field, and inparticular, to methods for transmitting and receiving a control channel,a base station, and a user equipment.

BACKGROUND

In downlink transmission in a long term evolution (LTE for short)Rel-8/9/10 communication system, an evolved base station (eNB for short)transmits a PDSCH (physical downlink shared channel) and a correspondingPDCCH (physical downlink control channel) to each scheduled userequipment according to a scheduling result.

The PDCCH is used to transmit scheduling indication signaling for uplinkor downlink data transmission of a user, where the scheduling indicationsignaling includes: resource allocation of a data channel, a modulationand coding scheme, and so on. Each PDCCH is made up of 1/2/4/8 controlchannel elements (CCE), respectively corresponding to different encodingrates. Each CCE is mapped to a group of specific time-frequency REs (RE)in a PDCCH region.

In a further evolution of an LTE Rel-10 system, MU MIMO (multiple usermultiple input multiple output) and multi-cell coordination need to besupported to improve system performance, and the number ofsimultaneously scheduled user equipments is increased by thesetechnologies; however, the capacity of the PDCCH is limited, whichlimits the number of user equipments that can be scheduled by a basestation. Therefore, the prior art enhances the PDCCH, that is, divides apart of resources from an original PDSCH (physical downlink sharedchannel) region, for transmitting an extended PDCCH, E-PDCCH(Extended-Physical Downlink Control Channel), thereby increasing thecapacity of the PDCCH and the number of simultaneously scheduled userequipments.

Because the introduced E-PDCCH needs to satisfy system configuration anduser configuration requirements that change continuously in transmissionand reception processes, an E-CCE (Extended-Control Channel Element,extended control channel element) that carries the E-PDCCH is requiredto keep changing semi-statically or dynamically. However, the E-CCE inthe prior art is fixed, and a transmission problem of available changingtransmission resources caused by introduction of the E-PDCCH cannot besolved. Therefore, the prior art has problems of low transmissionefficiency and too high transmission complexity in transmissioninvolving the E-PDCCH.

SUMMARY

Embodiments of the present invention provide methods for transmittingand receiving control channel, base station, and user equipment, a basestation, and a user equipment, which can solve a transmission problem ofavailable changing transmission resources caused by introduction of anE-PDCCH, improve transmission efficiency, and reduce transmissioncomplexity.

To achieve the preceding objective, embodiments of the present inventionadopt the following technical solutions:

In one aspect, a method for transmitting a control channel is providedand includes:

determining, according to a system configuration and/or userconfiguration, resource elements REs included in an extended controlchannel element E-CCE; and

transmitting an extended physical downlink control channel E-PDCCH to auser equipment, where the E-PDCCH is carried by the E-CCE.

In one aspect, a method for receiving a control channel is provided andincludes:

obtaining resource elements REs included in an extended control channelelement E-CCE, where the REs included in the E-CCE are determinedaccording to a system configuration and/or user configuration; and

receiving, over the REs included in the E-CCE, an extended physicaldownlink control channel E-PDCCH transmitted by a base station.

In another aspect, a base station is provided and includes:

a processing unit, configured to determine, according to a systemconfiguration and/or user configuration, resource elements REs includedin an extended control channel element E-CCE; and

a transmitting unit, configured to transmit an extended physicaldownlink control channel E-PDCCH to a user equipment, where the E-PDCCHis carried by the E-CCE.

In another aspect, a user equipment is provided and includes:

a processing unit, configured to obtain resource elements REs includedin an extended control channel element E-CCE, where the REs included inthe E-CCE are determined according to a system configuration and/or userconfiguration; and

a receiving unit, configured to receive, over the REs included in theE-CCE, an extended physical downlink control channel E-PDCCH transmittedby a base station.

In the methods for transmitting and receiving a control channel, thebase station, and the user equipment provided by the embodiments of thepresent invention, the base station determines, according to a systemconfiguration and/or user configuration, REs included in an E-CCE, andtransmits an E-PDCCH to the user equipment, where the E-PDCCH is carriedby the E-CCE; and the user equipment obtains, by using the same settingmethod as the base station, the REs included in the E-CCE, and receivesthe E-PDCCH over the REs included in the E-CCE. The E-CCE is set fixedlyand set dynamically or semi-statically, so that for available changingresources on the E-PDCCH carried by the E-CCE, a changing E-CCE iscorrespondingly available for transmission and reception, therebyimproving transmission efficiency, and reducing transmission complexity.

BRIEF DESCRIPTION OF THE DRAWINGS

To illustrate the technical solutions in the embodiments of the presentinvention or in the prior art more clearly, the following brieflyintroduces the accompanying drawings required for describing theembodiments. Apparently, the accompanying drawings in the followingdescription show merely some embodiments of the present invention, and aperson of ordinary skill in the art may still derive other drawings fromthese accompanying drawings without creative efforts.

FIG. 1 is a schematic flowchart of a method for transmitting a controlchannel according to an embodiment of the invention;

FIG. 2 is a schematic structural diagram of a mapping method fortransmission of a control channel according to an embodiment of theinvention;

FIG. 3 is a schematic structural diagram of another mapping method fortransmission of a control channel according to an embodiment of theinvention;

FIG. 4 is a schematic structural diagram of still another mapping methodfor transmission of a control channel according to an embodiment of theinvention;

FIG. 5 is a schematic structural diagram of still another mapping methodfor transmission of a control channel according to an embodiment of theinvention;

FIG. 6 is a schematic flowchart of a method for receiving a controlchannel resource according to an embodiment of the invention;

FIG. 7 is a schematic structural diagram of a base station according toan embodiment of the present invention;

FIG. 8 is a schematic structural diagram of another base stationaccording to an embodiment of the present invention;

FIG. 9 is a schematic structural diagram of a user equipment accordingto an embodiment of the present invention; and

FIG. 10 is a schematic structural diagram of another user equipmentaccording to an embodiment of the present invention.

DETAILED DESCRIPTION

The following clearly describes the technical solutions in theembodiments of the present invention with reference to the accompanyingdrawings in the embodiments of the present invention. Apparently, thedescribed embodiments are merely a part rather than all of theembodiments of the present invention. All other embodiments obtained bya person of ordinary skill in the art based on the embodiments of thepresent invention without creative efforts shall fall within theprotection scope of the present invention.

An embodiment of the present invention provides a method for configuringa control channel resource. As shown in FIG. 1, the method includes thefollowing steps:

S101. A base station determines, according to a system configurationand/or user configuration, REs included in an E-CCE.

Further, the base station determines an E-CCE according to the systemconfiguration and/or user configuration, which includes: determining anE-CCE of a first type that includes a fixed number of REs on a firstspecific resource; and determining an E-CCE of a second type thatincludes a semi-statically or dynamically changing number of REs on asecond specific resource.

It should be noted that only the E-CCE including a fixed number of REsis used in the prior art. However, more users need to be scheduled tojoin an E-PDCCH, where an E-CCE carrying the E-PDCCH is affected bydifferent system configurations or user configurations or actualtransmission conditions on the transmitted second specific resource,resulting in a change of the number of REs included in the E-CCE, butthe existing E-CCE cannot adapt to the change because it includes afixed number of REs. Therefore, at least one embodiment of the presentinvention provides an E-CCE of another type that includes a dynamicallychanging number of REs on the second specific resource, which is markedas an E-CCE of a second type, in addition to the existing E-CCE of thefirst type that includes a fixed number of REs on the first specificresource, and uses the changing number of REs included in the E-CCE ofthe second type to solve the transmission bearing problem of changingresources caused by introduction of an E-PDCCH.

Exemplarily, in the E-CCE of the first type and the E-CCE of the secondtype, the REs included in the E-CCE of the first type are fixed in afirst specific resource, for example, fixed and unchanged in a 5 msperiod of a CSI-RS (Channel State Information—Reference Signal, channelstate indicator-pilot symbol); the REs included in the E-CCE of thesecond type may change dynamically on each transmitted second specificresource block according to different system configurations and/or userconfigurations. For example, the number of REs included in a subframetransmitted for the first time is different from the number of REsincluded in a subframe transmitted for the second time. In the subframetransmitted for the first time, three E-CCEs respectively include 35,32, and 33 REs, while in the subframe transmitted for the second time,three E-CCEs respectively include 33, 31, and 34 REs. In the subframetransmitted for the second time, the number of subcarriers and thenumber of OFDM symbols included in a PDCCH are different from those inthe subframe transmitted for the first time, and pilot overheadsincluding a CSI-RS, a DMRS, and a CRS and overheads of other channelsare also different.

Consequently, the number of REs included in the E-CCE of the second typechanges dynamically.

Further, the E-CCE of the first type and the E-CCE of the second typeare mapped in the time domain and frequency domain respectivelyaccording to a certain rule, and the E-CCE of the first type and theE-CCE of the second type respectively have their own features, forexample, the port position of a demodulation pilot DMRS of the E-CCE ofthe first type is fixed, and the port position of a demodulation pilotDMRS of the E-CCE of the second type may change continuously accordingto a system presetting. For example, the DMRS port of the E-CCE of thefirst type may be port 7 and port 8, or may be port 7, port 8, port 9,and port 10; the DMRS port of the E-CCE of the second type may beindefinite, for example, any N of port 7, port 8, port 9, and port 10,where N is a positive integer greater than or equal to 1.

S102. The base station transmits an extended physical downlink controlchannel E-PDCCH to a user equipment, where the E-PDCCH is carried by theE-CCE.

Further, in a specific application, the E-CCE of the first type istransmitted in transmit diversity mode or open-loop beamforming mode;and the E-CCE of the second type is transmitted in open-loop beamformingmode. If the E-CCE of the first type is transmitted in transmitdiversity mode, the frequency domain may include 4M subcarriers, where Mis a positive integer greater than or equal to 1.

In the methods for transmitting and receiving a control channel, thebase station, and the user equipment provided by the embodiments of thepresent invention, the base station determines, according to a systemconfiguration and/or user configuration, REs included in an E-CCE, andtransmits an E-PDCCH to the user equipment, where the E-PDCCH is carriedby the E-CCE; and the user equipment obtains, by using the same settingmethod as the base station, the REs included in the E-CCE, and receivesthe E-PDCCH over the REs included in the E-CCE. The E-CCE is set fixedlyand set dynamically or semi-statically, so that for available changingresources on the E-PDCCH carried by the E-CCE, a changing E-CCE iscorrespondingly available for transmission and reception, therebyimproving transmission efficiency, and reducing transmission complexity.

Further, the base station performs calculation according to the numberof REs included in a resource set and the number of REs included inother overheads, and then rounds off the calculation result to obtainthe number of available REs in an E-CCE of a first type, where thenumber of available REs is marked as Z; and

if Z is greater than a preset first threshold and smaller than a presetsecond threshold, the base station sets Z to the number of REs includedin each E-CCE of the first type on the first specific resource;

or if Z is smaller than a preset first threshold, the base station setsthe first threshold to the number of REs included in each E-CCE of thefirst type on the first specific resource;

or if Z is greater than a preset second threshold, the base station setsthe second threshold to the number of REs included in each E-CCE of thefirst type on the first specific resource.

Exemplarily, the base station marks the total number of REs for carryingthe E-CCE of the first type in a resource set as Z according to thenumber of REs included in the resource set, for example, according tothe number of REs included in a PRB (Physical Resource Block, physicalresource block), or a PRB pair (Physical Resources Block pair, physicalresource block pair), or a PRG (Precoding Resource Group, precodingresource block group), or an RBG (Resource Block Group, resource blockgroup), or the number of REs included in a resource set divided intovarious E-CCE resources by the base station, for example, included in ahalf PRB; and predetermines overheads. For example, if the PDCCHincludes M REs, a DMRS overhead includes N REs, and a resource setfixedly has Y E-CCEs of the first type on the first specific resource,the number of REs included in each E-CCE of the first type is:Z=floor((X−M−N)/Y), that is, Z is rounded off to an integer, orZ=max(floor((X−M−N)/Y), A), where A is a lowest threshold set for thepurpose of reaching a demodulation effect by preventing the case thatthe number of calculated REs included in the E-CCE of the first type istoo small, where the lowest threshold is marked as a first threshold A,and the value may be a fixed constant and may also be changed accordingto the actual condition; or Z=min(floor((X−M−N)/Y) B), similarly, whereB is a preset second threshold B set for the purpose of avoiding wasteby preventing the case that the REs included in the E-CCE of the firsttype are far more than the resources needed for carrying, where B may bea fixed constant or may also be a variable.

It should be noted that the predetermined overheads include a pilotoverhead and overheads of other channels. For example, the pilotoverhead is a CSI-RS or a CRS or a DMRS, or a muted RE not transmittingany signal to avoid interference to the CSI-RS transmission position ofa neighboring cell; the overheads of other channels are one or more of aPDCCH channel overhead, a paging channel overhead, or a synchronizationchannel overhead. The pilot overhead on the first specific resource maybe one or more of the above pilot overheads. It should be noted that thepilot overhead on the first specific resource may be different from thepilot overhead on the second specific resource.

Or, exemplarily, the number of REs included in each E-CCE of the firsttype is calculated according to the total number of REs included in allE-CCEs of the first type and the number of REs included in thepredetermined overheads in the resource set and the number of E-CCEs ofthe first type in the resource set, and is marked as X; X is set to thenumber of REs included in each E-CCE of the first type on the firstspecific resource. The resource set may be all REs included in allE-CCEs of the first type in a PRB and is marked as L, but is not limitedto the number of REs included in a PRB in the above example. Because aPRB has REs not carrying any information, only REs carrying all E-CCEsof the first type are used for calculation, which may make thecalculation result more accurate. The calculation method may also be themethod illustrated in the above example, where X=floor ((L−M−N)/Y) orX=max(floor((L−M−N)/Y), A) or Z=min (floor ((X−M−N)/Y), B). The use ruleis described in the above example and will not be further describedherein.

Further, the base station may preset the number of REs included in eachE-CCE of the first type on the first specific resource, where the numberof REs is marked as K, and sets K to the number of REs included in eachE-CCE of the first type on the first specific resource. Therefore, nocalculation is required and the operation step can be simplified.

Or, exemplarily, the base station divides the resource set according tothe number of E-CCEs of the first type to obtain resource subsets. Forexample, if a PRB has three E-CCEs of the first type, the base stationregards all REs included in each E-CCE of the first type as a resourcesubset, obtains a unique value by using a specific function according tothe number of available REs obtained after the predetermined overheadsare subtracted from each resource subset, and sets the unique value tothe number of REs included in each E-CCE of the first type on the firstspecific resource. For example, a specific function is used forcalculation to obtain the minimum value of the numbers of the REsincluded in the E-CCEs of the first type in the resource subsets, andthe minimum value is set to the number of REs included in each E-CCE ofthe first type.

Further, the base station sets the number of REs included in each E-CCEof the first type according to the fixed position of each E-CCE of thefirst type on a subcarrier and a fixed position including an orthogonalfrequency division multiplexing OFDM symbol, and fixes the subcarrierposition of each E-CCE and the position of the OFDM symbol; the numberof the subcarrier occupied by each E-CCE and the number of the OFDMsymbol are fixed. It is assumed that: the first E-CCE of the first typeincludes #0 subcarrier to #2 subcarrier, which include #0 OFDM symbol to#13 OFDM symbol; the second E-CCE of the first type includes #3subcarrier to #5 subcarrier, which include #0 OFDM symbol to #13 OFDMsymbol, and so on. If four E-CCEs of the first type exist now, and thenumber of available REs for the first E-CCE of the first type after theRS (Reference Signal, pilot signal) overheads of other channels aresubtracted is X1, the number of available REs for the second E-CCE ofthe first type after the RS overheads of other channels are subtractedis X2, the number of available REs for the third E-CCE of the first typeis X3, and the number of available REs for the fourth E-CCE of the firsttype is X4, the number of REs included in each E-CCE of the first typeis fixedly Y=f(X1, X2, X3, X4); the number of REs included in each E-CCEof the first type is set to a proper value, and the number of REsoccupied by each E-CCE of the first type on the first specific resourceis set according to the fixed value.

Or, exemplarily, the base station may also divide the resource setaccording to the number of E-CCEs of the first type to obtain resourcesubsets, and respectively set the number of available REs after thepredetermined overheads are subtracted from each resource subset to thenumber of REs included in each E-CCE of the first type on the firstspecific resource; if a PRB includes three E-CCEs, and each E-CCE of thefirst type is used as a resource subset, the base station calculates thenumber of REs included in each E-CCE of the first type by subtractingthe predetermined overheads, and then sets the number of REs included ineach E-CCE to the number of REs included in the E-CCE of the first type,and does not use a uniform value so that all E-CCEs include the samenumber of REs; therefore, accuracy is high. Assuming that the REposition occupied by each E-CCE of the first type is fixed, the basestation sets, according to the number of REs obtained after thepredetermined overheads are subtracted from the total number of REpositions included in a same E-CCE of the first type, the number of REsincluded in the E-CCE of the first type; for example, the fixed positionof the first E-CCE of the first type is (k1, M1), where k1 is the numberof a subcarrier, and M1 is the number of an OFDM symbol, and the fixedposition of the second E-CCE of the first type is (k2, M2), where k2 isthe number of a subcarrier, and M2 is the number of an OFDM symbol, andso on. Still assuming that four E-CCEs of the first type exist, the basestation adds up all REs included in the fixed positions of the firstE-CCE of the first type to obtain the number of REs included in thefirst E-CCE of the first type on the first specific resource, and so on,obtains the number of REs respectively included in the four E-CCEs ofthe first type, and correspondingly performs a setting, so that thenumber of REs included in each E-CCE of the first type is different.

Or, exemplarily, the base station may further correspondingly set,according to the preset PRG, or RBG, or system bandwidth, or configuredcontrol channel bandwidth, or different aggregation levels, or differentparameters of different E-CCEs at a same aggregation level, the numberof REs included in the E-CCE of the first type on the first specificresource, as shown in Tables 1, 2, 3, 4, and 5, and correspondinglyobtain the number of REs included in the E-CCE of the first type on thefirst specific resource, and set the number of REs to the number of REsincluded in each E-CCE of the first type on the first specific resource.

TABLE 1 System Number of REs Included in the Bandwidth E-CCE of theFirst Type ≦10 X1 11-26 X2 27-63 X3  64-110 X4

TABLE 2 Configured Number of REs Included in the E-PDCCH Bandwidth E-CCEof the First Type Y1 X1 Y2 X2 Y3 X3 Y4 X4

TABLE 3 Number of REs Included in the RBG E-CCE of the First Type Z1 X1Z2 X2 Z3 X3 Z4 X4

TABLE 4 Number of REs Included in the PRG E-CCE of the First Type W1 X1W2 X2 W3 X3 W4 X4

TABLE 5 Number of E-CCEs E-PDCCH Included at the Number of REs Includedin the Format Aggregation Level E-CCE of the First Type F1 M1 K1 F2 M2K2 F3 M3 K3 F4 M4 K4

The above methods are several examples about how the base station setsthe number of REs of the E-CCE of the first type on the first specificresource; the following methods are several examples about setting thenumber of REs of the E-CCE of the second type on the second specificresource. It should be noted that any one of the above methods forsetting the number of REs of the E-CCE of the first type on the firstspecific resource is used with any one of the following methods forsetting the number of REs of the E-CCE of the second type on the secondspecific resource, which is not limited in any way.

Exemplarily, the base station performs calculation according to thenumber of REs included in the current resource set and the number of REsincluded in other overheads, and then rounds off the calculation resultto obtain the number of available REs included in an E-CCE, where thenumber of available REs is marked as Z′;

if Z is greater than a preset first threshold and smaller than a presetsecond threshold, the base station sets Z′ to the number of REs occupiedcurrently by each E-CCE of the second type on the second specificresource;

or if Z′ is smaller than a preset first threshold C, the base stationsets C to the number of REs currently occupied by each E-CCE of thesecond type on the second specific resource;

or if Z is greater than a preset second threshold D, the base stationsets D to the number of REs currently occupied by each E-CCE of thesecond type on the second specific resource.

It should be noted that because the resource set transmitted by the basestation every time is different according to the system configurationand/or actual transmission condition, the base station subtracts thenumber of REs included in various pilot RSs from the total number L ofREs for carrying the E-CCE of the second type in the current resourceset. For example, if a CSI-RS includes S REs, a DMRS includes N REs, andoverheads of a PDCCH and other channels include MREs, the number of REsincluded in each E-CCE of the second type is obtained by calculation:Z′=floor((L−M−N−S)/Y), or Z′=max(floor((L−M−N−S)/Y), C), orZ′=min(floor((L−M−N−S)/Y), D). The principle of setting C and D is thesame as that of setting A and B in the E-CCE of the first type, and willnot be further described herein.

It should be noted that the base station may further perform the abovecalculation according to the total number X of the REs for carrying inthe search position of the E-CCE of the second type in the controlchannel, so as to more accurately obtain the number of REs of the E-CCEof the second type on the specific resource. For example, the searchspace of the E-CCE of the second type is in the middle position of anRBG, where the total number of the REs for carrying is L. For example,the search position space of the E-CCE of the second type in the controlcharmel is in the middle position of an RBG, where the number of REsincluded in each E-CCE is calculated according to the total number L ofREs for carrying, the number of REs included in the predeterminedoverheads, and the number Y of E-CCEs in the resource set and marked asX′, and X′ is set to the number of REs included in each E-CCE of thesecond type on the second specific resource. It should be noted that thecalculation method may also be the method in the above example, whereX=floor ((L−M−N)/Y) or X′=max (floor ((L−M−N)/Y), A) orX′=min(floor((L−M−N)/Y), B); the use rule is described in the aboveexample, and will not be further described herein.

It should be noted that the predetermined overheads are described indetail in the above content and will not be further described herein.However, the pilot overhead of the E-CCE of the second type may bedifferent from that of the E-CCE of the first type, and is not limitedby the E-CCE of the first type in any way.

Or, exemplarily, according to the preset number, which is marked as Y′,of REs currently included in each E-CCE of the second type on the secondspecific resource, the base station sets Y′ to the number of REscurrently included in each E-CCE of the second type on the secondspecific resource, and no calculation is further required.

Or, exemplarily, the base station divides the resource set according tothe current number of E-CCEs of the second type to obtain resourcesubsets, obtains a unique value by using a current specific functionaccording to the number of available REs obtained after thepredetermined overheads are subtracted from each resource subset, andsets the unique value to the number of REs currently included in eachE-CCE of the second type on the second specific resource.

It is assumed that: the position of each E-CCE of the second type on thecurrent second specific resource is fixed on a subcarrier, and aposition including an orthogonal frequency division multiplexing OFDMsymbol every time is fixed; the current subframe has four E-CCEs of thesecond type; the first E-CCE of the second type includes #4 subcarrierto #7 subcarrier, which include #5 OFDM symbol to #9 OFDM symbol; thesecond E-CCE of the second type includes #3 subcarrier to #7 subcarrier,which include #5 OFDM symbol to #9 OFDM symbol, and so on. If fourE-CCEs of the second type exist now, and the number of available REs forthe first E-CCE of the second type after the overhead of the RS underthe current channel condition, especially the overhead of the CSI-RS,and overheads of other channels are subtracted is Y1′, the number ofavailable REs for the second E-CCE of the second type after the overheadof the RS and overheads of other channels are subtracted is Y2′, and noCSI-RS in the fixed position set for the second E-CCE of the second typeincludes an RE, the overhead of the CSI-RS does not need to besubtracted during calculation; if the number of available REs for thethird E-CCE of the second type is Y3′, and the number of available REsfor the fourth E-CCE of the second type is Y4′, the number of REsincluded in each E-CCE of the second type is fixedly Z′=f (Y1′, Y2′,Y3′, Y4′).

Preferably, the base station may select the minimum value of the numbersof available REs for carrying in the E-CCEs of the second type as thenumber of REs occupied by each E-CCE of the second type on the secondspecific resource, that is, Y′=min(Y1′, Y2′, Y3′, Y4′), and set Y′ tothe number of REs occupied by each E-CCE of the second type.

It should be noted that the number of REs included in the E-CCE of thesecond type is only applicable to the current second specific resource;on the next second specific resource, the number of REs included in theE-CCE of the second type is reset.

Or, exemplarily, the base station divides the resource set according tothe current number of E-CCEs of the second type or a preset integer toobtain resource subsets, and sets the number of available REs obtainedafter other overheads are subtracted from each resource subset, to thenumber of REs included in each E-CCE of the second type on the currentsecond specific resource. Because each resource subset also has some REsthat do not carry any information and are not included in the totalnumber L, the method of calculation according to the total number of REsactually included in each E-CCE of the second type precludes the impactcaused by the REs not carrying any information on calculation accuracy,so that the calculation result is more accurate.

For example, the serial number of a subcarrier occupied by each E-CCE ofthe second type on the second specific resource and the serial number ofan OFDM symbol are fixed. It is assumed that: the first E-CCE of thesecond type includes #0 subcarrier to #2 subcarrier, which include #0OFDM symbol to #13 OFDM symbol; the second E-CCE of the second typeincludes #3 subcarrier to #5 subcarrier, which include #0 OFDM symbol to#13 OFDM symbol, and so on. If four E-CCEs of the second type exist now,and the number of available REs for the first E-CCE of the second typeafter the overhead of the RS (Reference Signal, pilot signal) andoverheads of other channels and so on are subtracted is Y1′, the numberof available REs for the second E-CCE of the second type after theoverhead of the RS and overheads of other channels are subtracted isY2′, the number of available REs for the third E-CCE of the second typeis Y3′, and the number of available REs for the fourth E-CCE of thesecond type is Y4′, the number of REs included in each E-CCE of thesecond type is fixedly Y=f(Y1′, Y2′, Y3′, Y4′); the number of REsincluded in each E-CCE of the second type is set to a proper value, andthe number of REs occupied by each E-CCE of the second type on thesecond specific resource is set according to the fixed value.

Or, exemplarily, the base station may also divide the resource setaccording to the current number of E-CCEs of the second type or a presetinteger to obtain resource subsets, and set the number of available REsobtained after other overheads are subtracted from each resource subset,to the number of REs included in each E-CCE of the second type on thecurrent second specific resource, so that each E-CCE of the second typeincludes a different number of REs according to its own specificcondition.

Or, exemplarily, the base station may further correspondingly set,according to the preset PRG, or RBG, or system bandwidth, or configuredcontrol channel bandwidth, or different aggregation levels, or differentparameters of different E-CCEs at a same aggregation level, the numberof REs included in the E-CCE of the second type on the second specificresource, as shown in Tables 6, 7, 8, 9, and 10, and correspondinglyobtain the number of REs included in the E-CCE of the second type on thesecond specific resource, and set the number of REs to the number of REsincluded in each E-CCE of the second type on the second specificresource.

TABLE 6 System Pilot and Other Number of REs Included in the BandwidthOverheads E-CCE of the Second Type ≦10 M1 K1 11-26 M2 K2 27-63 M3 K3 64-110 M4 K4

TABLE 7 Configured Pilot and Other Number of REs Included in the E-PDCCHBandwidth Overheads E-CCE of the Second Type Y1 M1 K1 Y2 M2 K2 Y3 M3 K3Y4 M4 K4

TABLE 8 Pilot and Other Number of REs Included in the RBG OverheadsE-CCE of the Second Type Z1 M1 K1 Z2 M2 K2 Z3 M3 K3 Z4 M4 K4

TABLE 9 Pilot and Other Number of REs Included in the PRG OverheadsE-CCE of the Second Type W1 M1 K1 W2 M2 K2 W3 M3 K3 W4 M4 K4

TABLE 10 Number of E-CCEs E-PDCCH Included at the Number of REs Includedin the Format Aggregation Level E-CCE of the Second Type F1 M1 K1 F2 M2K2 F3 M3 K3 F4 M4 K4

It should be noted that Table 10 reflects that the number of REsoccupied by different E-CCEs of the second type at a same aggregationlevel is different; during the setting, the numbers of REs occupied byE-CCEs of the second type at the same aggregation level may bedifferent. For example, the number of REs included in the E-CCE of thesecond type at aggregation level 1 is 4, and the number of REs includedin another E-CCE of the second type at aggregation level 1 is 5.

It should be noted that the number of REs included in the PRG is decidedaccording to the configured control channel region, and consists of PRBsor E-CCEs. The method for setting the control channel region isdifferent from the method for setting the PDSCH region, and may beobtained correspondingly according to Table 11.

TABLE 11 Resource Size Configured for the PRG Size of the E-PDCCH RegionControl Channel F1 F1 F2 F2 F3 F3 F4 F4

In the methods for transmitting and receiving a control channel, thebase station, and the user equipment provided by the embodiments of thepresent invention, the base station determines, according to a systemconfiguration and/or user configuration, REs included in an E-CCE, andtransmits an E-PDCCH to the user equipment, where the E-PDCCH is carriedby the E-CCE; and the user equipment obtains, by using the same settingmethod as the base station, the REs included in the E-CCE, and receivesthe E-PDCCH over the REs included in the E-CCE. The E-CCE is set fixedlyand set dynamically or semi-statically, so that for available changingresources on the E-PDCCH carried by the E-CCE, a changing E-CCE iscorrespondingly available for transmission and reception, therebyimproving transmission efficiency, and reducing transmission complexity.

Furthermore, the above embodiment of the present invention describes howthe base station sets the number of REs included in the E-CCE of thefirst type on the first specific resource or the number of REs includedin the E-CCE of the second type on the second specific resource. Thefollowing embodiment uses examples to describe how to map the E-CCE ofthe first type and the E-CCE of the second type.

As shown in FIG. 2, 20 represents an RE, 21 represents an RE included ina DMRS pilot, 22 represents an RE included in a CRS (Cell-specificReference Signal, cell pilot signal), 23 represents a PRE, 24 representsa PRG or an RBG, and 25 represents a start point position of an E-CCE ofa first type. From a preset start point of the E-CCE of the first type,first in a frequency domain and then in a time domain, or first in atime domain and then in a frequency domain, the REs included in theE-CCE of the first type are mapped, where if more than one RE occupiedby other overheads exists during the mapping, the E-CCE of the firsttype is not mapped in RE positions occupied by the overheads, and theREs occupied by the overheads are correspondingly subtracted from thenumber of REs included in the E-CCE of the first type; or RE positionsoccupied by the overheads are skipped, and the determined number of REsincluded in the E-CCE of the first type are mapped; or the number of REsincluded in the E-CCE of the first type are mapped directly from apreset start point, and a control channel mapped to the positionsoccupied by the overheads is punched for transmitting the overheads.

From a preset start point of an E-CCE of a second type, mapping isperformed according to any one of the above methods, which will not befurther described herein.

Exemplarily, in a configured control channel region, the E-CCE of thefirst type or the E-CCE of the second type has an equal spacing betweensearch start points or search spaces in the frequency domain, where thespacing is at least one subcarrier, or has an equal spacing betweensearch start points or search spaces in the time domain, where thespacing is at least one orthogonal frequency division multiplexing OFDMsymbol. As shown in FIG. 3, within the range of each PRB, PRB pair, PRG,or REG in the configured control channel region, the position of thesearch start point or search space of the E-CCE of the first type isfixed in the frequency domain. For example, the E-CCE of the first typeis mapped on the subcarrier of f_(i)εF1, and the E-CCE of the secondtype is mapped on the subcarrier of f_(i)εF2. The subcarrier set F1 maybe divided into N subcarrier groups. In each subcarrier group, thesubcarriers are continuous, and the distance between N subcarrier groupsis fixed. As shown in FIG. 3, 30 represents an RE, 31 represents an REincluded in a DMRS pilot, 32 represents an RE included in a CRS, 33represents a PRB, 35 represents a search start point or search space ofthe E-CCE of the first type, and 36 represents a search start point orsearch space of the E-CCE of the second type.

Or, the search start point or search space of the E-CCE of the firsttype is mapped in a fixed position of each PRB, PRB pair, PRG, or RBG ona subcarrier in the frequency domain; assuming that the position of theE-CCE of the first type is fixed in the range of each PRB, PRB pair,PRG, or RBG, and that the fixed position is reserved by a higher-layerconfiguration, as shown in FIG. 4, 40 represents an RE, 41 represents anRE included in a DMRS pilot, 42 represents an RE included in a CRS, 43represents a PRB, 44 represents a PRG or an RBG, 45 represents thesearch start point or search space of the E-CCE of the first type, 46represents the search start point or search space of the E-CCE of thesecond type, and the search start point or search space of the E-CCE ofthe first type is fixed in a middle position between two PRBs.

Or, the E-CCE of the first type crosses two adjacent PRBs in a PRG or anRBG. For example, search start points or search spaces of two adjacentE-CCEs of the first type, as shown in FIG. 5, are fixed in the middleposition of each PRB, where 50 represents an RE, 52 represents an REincluded in a DMRS pilot, 51 represents an RE included in a CRS, 53represents a PRB, 54 represents a PRG or an RBG, 55 represents a searchstart point or search space of the E-CCE of the first type, and 56represents a search start point or search space of the E-CCE of thesecond type. In the above description about FIG. 5, examples are onlyused to describe the case that the position of the search start point orsearch space of the E-CCE of the first type is fixed in the frequencydomain, and the position is not limited in any way.

It should be noted that: E-CCEs of the first type in a same PRG have asame precoding vector and E-CCEs of the second type have a sameprecoding vector; the search space of the E-CCE of the first type andthe search space of the E-CCE of the second type are used by frequencydivision multiplexing or time division multiplexing in a PRB, a PRG, oran REG, and E-CCEs of a same type in a same PRG have a same precodingvector for performing joint channel estimation.

In another aspect, when the E-CCE of the second type is mapped in thefrequency domain, the search start point or search space of the E-CCE ofthe second type may be fixed, where the fixed position relationship maybe as shown in the above figures. However, it should be noted that thesearch start point or search space of the E-CCE of the second type isonly fixed on the current transmitted second specific resource, and anymode of fixing the search start point or search space of the E-CCE ofthe second type may match any mode of fixing the search start point orsearch space of the E-CCE of the first type, which is not limited in anyway.

In addition, when multiplexing is performed in the time domain, theE-CCE of the first type is mapped to a first resource set, where thefirst resource set includes a first subframe set or a first timeslot setor a first OFDM set; the E-CCE of the second type is mapped to a secondresource set, where the second resource set includes a second subframeset or a second timeslot set or a second OFDM set; and the firstresource set and the second resource set have an intersection or do nothave an intersection.

It is assumed that: the E-CCE of the first type includes an OFDM symbolof n_(i)εA1, and is mapped to the timeslot of n_(s)εB1 or to thesubframe of n_(f)εC1; the E-CCE of the second type includes an OFDMsymbol of n_(i)εA2, and is mapped to the timeslot of n_(s)εB2 or to thesubframe of n_(f)εC2, where A1 and A2 sets may have no intersection ormay be partially intersected; B1 and B2 may have no intersection or maybe partially intersected; C1 and B2 sets may have no intersection, ormay be partially intersected.

The first resource set is a resource set including no CSI-RS or amulticast broadcast single frequency network MBSFN set; if the firstresource set and the third resource set that includes a CSI-RS have anintersection, no CSI-RS is transmitted over time resources colliding inthe intersection. If C1 is a subframe including no CSI-RS, or an MBSFN(Multicast Broadcast Single Frequency Networks, multicast broadcastsingle frequency network) subframe, the MBSFN subcarrier carries fewpilots and does not carry a CSI-RS.

Or, if the subframe set C1 includes #1, #2, #3, #5, and #9, while theCSI-RS in another subframe set C3 includes #3, #4, #5, and #6, whichmeans that the two subframe sets have a set collision on #3 and #5, inthis case, #3 and #5 do not carry any information; the subframe set C1does not transmit the E-CCE of the first type on #3 and #5; and thesubframe set C3 does not transmit the CSI-RS on #3 and #5.

A1, A2, B1, B2, C1, and C2 are configured by a higher layer, or areconfigured fixedly according to a predetermined rule.

It should be noted that the E-CCE of the first type and the E-CCE of thesecond type have their own use spaces. Exemplarily, because the E-CCEcarrying the E-PDCCH region is divided into a common search space and auser-specific search space, the E-CCE of the first type is used for thecommon search space, and the E-CCE of the second type is used for theuser-specific search space.

Or, E-CCEs using different resource mapping modes are mapped to E-CCEsof different types, where, an E-CCE using discrete resource mapping isan E-CCE of the first type, and an E-CCE using centralized resourcemapping is an E-CCE of the second type.

Or, when the control channel is scrambled by different RNTIs, the E-CCEof the first type or the E-CCE of the second type is used, where theE-CCE of the first type is used when the control channel is scrambled byan SI-RNTI (system information Radio Network Temporary Identifier), aP-RNTI (paging Radio Network Temporary Identifier), an RA-RNTI (randomaccess Radio Network Temporary Identifier), and an SPS C-RNTI(Semi-Persistent Scheduling C-RNTI), while the E-CCE of the second typeis used when the control channel is scrambled by a C-RNTI.

Another case is that, according to different channel formats of controlchannels, the E-CCE of the first type or the E-CCE of the second type isused. For example, all control channel formats DCI formats are dividedinto the following groups: 1, 1A, 3, 3A, 2, 2B, and 2C, where fi is usedto indicate a DCI format; the first group includes (f1, f2, . . . ,f_(N)), and the second group includes (f_(N+1), f_(N)), where the firstgroup uses the E-CCE of the first type and the second group uses theE-CCE of the second type.

In the methods for transmitting and receiving a control channel, thebase station, and the user equipment provided by the embodiments of thepresent invention, the base station deteLmines, according to a systemconfiguration and/or user configuration, REs included in an E-CCE, andtransmits an E-PDCCH to the user equipment, where the E-PDCCH is carriedby the E-CCE; and the user equipment obtains, by using the same settingmethod as the base station, the REs included in the E-CCE, and receivesthe E-PDCCH over the REs included in the E-CCE. The E-CCE is set fixedlyand set dynamically or semi-statically, so that for available changingresources on the E-PDCCH carried by the E-CCE, a changing E-CCE iscorrespondingly available for transmission and reception, therebyimproving transmission efficiency, and reducing transmission complexity.

An embodiment of the present invention provides a method for receiving acontrol channel. As shown in FIG. 6, the method includes the followingsteps:

S201. A user equipment obtains resource elements REs included in anextended control channel element E-CCE, where the REs included in theE-CCE are determined according to a system configuration and/or userconfiguration.

Further, the user equipment obtains, on a first specific resource, anE-CCE of a first type including a fixed number of REs; and/or obtains,on a second specific resource, an E-CCE of a second type including avariable number of REs.

Exemplarily, the user equipment obtains, according to resource elementsREs included in a resource set and REs of predetermined overheads in theresource set, resource elements REs included in an extended controlchannel element E-CCE.

Specifically, the user equipment performs calculation according to thenumber of REs included in the resource set and the number of REsincluded in the predetermined overheads, and then rounds off thecalculation result to obtain the number of available REs included in anE-CCE, where the number of available REs is marked as Z; and

if Z is greater than a preset first threshold and smaller than a presetsecond threshold, the user equipment determines Z as the number of REsincluded in each E-CCE of the first type on the first specific resource;or if Z is smaller than a preset first threshold, determines the firstthreshold as the number of REs included in each E-CCE of the first typeon the first specific resource; or if Z is greater than a preset secondthreshold, determines the second threshold as the number of REs includedin each E-CCE of the first type on the first specific resource.

The resource set is a PRB, or a PRB pair, or a PRG, or an RBG, or a setdivided into various E-CCE resources. Other overheads include at leastone of a pilot overhead and/or overheads of other channels, for example,the pilot overhead may be a channel state indicator-pilot symbol CSI-RSor a cell pilot signal CRS or a demodulation pilot DMRS or a muted RE;and the overheads of other channels may be a paging channel overhead ora synchronization channel overhead.

Or, exemplarily, the number of REs included in each E-CCE of the firsttype is calculated according to the number of REs included in theresource set and the number of REs included in the predeterminedoverheads and the number of E-CCEs in the resource set, and is marked asX, where X is set to the number of REs included in each E-CCE of thefirst type on the first specific resource.

Or, the number of REs included in each E-CCE of the first type on thefirst specific resource is preset and marked as Y, where Y is set to thenumber of REs currently included in each E-CCE of the first type on thefirst specific resource.

Or, exemplarily, the user equipment divides the resource set accordingto the number of E-CCEs to obtain resource subsets, obtains a uniquevalue by using a specific function according to the number of availableREs obtained after the predetermined overheads are subtracted from eachresource subset, and determines the unique value as the number of REsincluded in the each E-CCE of the first type on the first specificresource. For example, the user equipment obtains the unique value byusing a specific function, where the unique value is the minimum valueof the number of available REs obtained after other overheads aresubtracted from each resource subset.

Or, the user equipment divides, according to the number of E-CCEs, theresource set carrying the E-PDCCH to obtain resource subsets, andrespectively determines the number of available REs obtained after otheroverheads are subtracted from each resource subset, as the number of REsincluded in each E-CCE of the first type in the first specific resource.

Or, the user equipment determines the number of REs included in eachE-CCE of the first type in the first specific resource correspondinglyaccording to Tables 1 to 5 of the above configuration method embodiment.That is, the user equipment correspondingly determines the number of REsincluded in the E-CCE of the first type according to the PRG or RBG orsystem bandwidth or configured control channel bandwidth or differentaggregation levels or different parameters of different E-CCEs at a sameaggregation level.

The number of REs included in the E-CCE of the second type on thecurrent second specific resource may be determined according to any oneof the above methods. It should be noted that when the number of REsoccupied by the E-CCE of the second type is determined, thepredetermined overheads may be different from those of the E-CCE of thefirst type. The detailed determining method may be determined accordingto the setting method of a base station, which is known to the userequipment, and will not be further described herein.

The user equipment performs resource demapping for the received E-CCE ofthe first type or E-CCE of the second type according to the number ofREs respectively included therein, for example, performs resourcedemapping for the REs included in the E-CCE of the first type, from apreset start point of the E-CCE of the first type, first in a frequencydomain and then in a time domain, or first in a time domain and then ina frequency domain; and if REs occupied by other overheads exist duringthe resource demapping, does not perform resource demapping for theE-CCE of the first type in RE positions occupied by the overheads, wherethe REs that are occupied by the overheads are correspondinglysubtracted from the number of REs included in the E-CCE of the firsttype; or skips RE positions occupied by the overheads, and keepsperforming resource demapping until the determined number of REsincluded in the E-CCE of the first type.

From a preset start point of the E-CCE of the second type, resourcedemapping is performed according to any one of the above methods, whichwill not be further described herein.

Further, the E-CCE of the first type or the E-CCE of the second type isdetected, and the E-CCE of the first type or the E-CCE of the secondtype is detected according to the search start point or search space ofthe E-CCE of the first type or the E-CCE of the second type predicted bythe user equipment.

Exemplarily, in a configured control channel region, the E-CCE of thefirst type or the E-CCE of the second type has an equal spacing betweensearch start points or search spaces in the frequency domain, where thespacing is at least one subcarrier, or has an equal spacing betweensearch start points or search spaces in the time domain, where thespacing is at least one orthogonal frequency division multiplexing OFDMsymbol.

Or, in the range of each PRB, PRB pair, PRG, or RBG in a configuredcontrol channel region, the position of the search start point or searchspace of the E-CCE of the first type or the E-CCE of the second type isfixed.

Or, the E-CCE of the first type crosses two adjacent PRBs in a PRG or anRBG.

It should be noted that the number of REs included in the PRG, duringPRG detection, is decided according to the configured control channelregion, and consists of PRBs or E-CCEs. The method for setting thecontrol channel region is different from the method for setting thephysical downlink shared channel PDSCH region.

In the time domain, the E-CCE of the first type is detected in a firstresource set, where the first resource set includes a first subframe setor a first timeslot set or a first OFDM symbol set; the E-CCE of thesecond type is detected in a second resource set, where the secondresource set includes a second subframe set or a second timeslot set ora second OFDM symbol set; and the first resource set and the secondresource set have an intersection or do not have an intersection.

Further, the first resource set is a resource set including a CSI-RS oris a multicast broadcast single frequency network MBSFN resource set;and if the first resource set and a third resource set that includes aCSI-RS have an intersection, no CSI-RS exists in the intersection of theresource sets.

During the detection, the corresponding information may be obtainedaccording to the fact that the demodulation pilot DMRS port of the E-CCEof the first type is fixed and that the demodulation pilot DMRS port ofthe E-CCE of the second type is dynamically changeable.

Or, the user equipment detects the E-CCE of the first type in transmitdiversity mode or precoding mode, and detects the E-CCE of the secondtype in precoding mode.

It should be noted that: the E-CCE of the first type is detected in thecommon search space; the E-CCE of the second type is detected in theuser-specific search space. When the E-CCE of the first type is detectedin the common search space, before the CSI-RS configuration or other RRCsignaling is received, the E-CCE of the first type may be detected inthe user-specific search space according to the number of REs includedin the E-CCE of the first type; after the CSI-RS configuration or otherRRC signaling is received, the E-CCE of the second type may be detectedin the user-specific search space.

In addition, the user equipment detects the E-CCE of the first type orthe E-CCE of the second type according to the control channel scrambledby different radio network temporary identifiers, or detects the E-CCEof the first type or the E-CCE of the second type according to thedownlink control information DCI format group of the control channel.

S202. The user equipment receives, over the REs included in the E-CCE,an extended physical downlink control channel E-PDCCH transmitted by abase station.

It should be noted that the user equipment may further determine,according to the broadcast notification, system informationnotification, or RRC signaling notification which are transmitted by thebase station, the number of REs included in the E-CCE of the first typeor the E-CCE of the second type, or obtain, from a common controlchannel notification, the number of REs included in the CCE of thesecond type and the second specific resource.

Further, the user equipment may further determine whether it is an E-CCEof the first type or an E-CCE of the second type according to the startpoint of the CCE, or determine respective start points according to theE-CCE of the first type or the E-CCE of the second type.

In this embodiment, the user equipment may perform resource demappingand detecting according to the same setting method and mapping methodknown to the base station, and the repeated steps will not be furtherdescribed herein.

In the methods for transmitting and receiving a control channel, thebase station, and the user equipment provided by the embodiments of thepresent invention, the base station determines, according to a systemconfiguration and/or user configuration, REs included in an E-CCE, andtransmits an E-PDCCH to the user equipment, where the E-PDCCH is carriedby the E-CCE; and the user equipment obtains, by using the same settingmethod as the base station, the REs included in the E-CCE, and receivesthe E-PDCCH over the REs included in the E-CCE. The E-CCE is set fixedlyand set dynamically or semi-statically, so that for available changingresources on the E-PDCCH carried by the E-CCE, a changing E-CCE iscorrespondingly available for transmission and reception, therebyimproving transmission efficiency, and reducing transmission complexity.

A base station 60 provided by an embodiment of the present invention, asshown in FIG. 7, includes a processing unit 601 and a transmitting unit602.

The processing unit 601 is configured to determine, according to asystem configuration and/or user configuration, resource elements REsincluded in an extended control channel element E-CCE.

Exemplarily, as shown in FIG. 7, the processing unit 601 includes asetting module 6011 and a mapping module 6012.

The setting module 6011 is configured to determine, according toresource elements REs included in a resource set and REs ofpredetermined overheads in the resource set, resource elements REsincluded in an extended control channel element E-CCE.

The setting module 6011 is specifically configured to: obtain, accordingto the number of REs included in a resource set and the number of REs ofpredetermined overheads in the resource set, the number of available REsin the resource set; obtain, according to the number of available REs inthe resource set and the number of REs of predetermined overheads in theresource set, the number of REs available for each E-CCE; and determine,according to the number of REs available for each E-CCE, the number ofREs included in each E-CCE.

Or, the setting module 6011 is specifically configured to: if the numberof REs available for each E-CCE is greater than a preset first thresholdand smaller than a preset second threshold, determine the number of REsavailable for each E-CCE as the number of REs included in each E-CCE; ifthe number of REs available for each E-CCE is smaller than a presetfirst threshold, set the first threshold to the number of REs includedin each E-CCE on a specific resource; and/or if the number of REsavailable for each E-CCE is greater than a preset second threshold, setthe second threshold to the number of REs included in each E-CCE on aspecific resource.

Or, the setting module 6011 is specifically configured to: divide aresource set according to the predetermined number of E-CCEs in theresource set to obtain resource subsets; obtain, according to the numberof REs included in each resource subset and the number of REs ofpredetermined overheads in each resource subset, the number of availableREs in each resource set; and determine, according to the number ofavailable REs in each resource subset, the number of REs included ineach E-CCE in the resource set.

Or, the setting module 6011 is specifically configured to determine,according to at least one of a preset precoding resource block groupPRG, a resource block group REG, a system bandwidth, a configuredcontrol channel bandwidth, different aggregation levels, and differentparameters of different E-CCEs at a same aggregation level, the numberof REs included in the E-CCE.

The mapping module 6012 is configured to: map, from a preset start pointof the E-CCE, first in a frequency domain and then in a time domain, orfirst in a time domain and then in a frequency domain, the REs includedin the E-CCE, where if REs occupied by the predetermined overheads existduring the mapping, the E-CCE is not mapped in RE positions occupied bythe predetermined overheads, and the REs occupied by the predeterminedoverheads are correspondingly subtracted from the number of REs includedin the E-CCE; or skip RE positions occupied by the predeterminedoverheads, and map the number of REs included in the E-CCE; or map thenumber of REs included in the E-CCE from a preset start point of theE-CCE, where a control channel mapped to the REs occupied by thepredetermined overheads is punched for transmitting the predeterminedoverheads.

It should be noted that the E-CCEs are grouped, according to the numberof included REs, into an E-CCE of a first type having a fixed number ofincluded REs, and an E-CCE of a second type having a dynamicallychangeable number of included REs; the processing unit 601 performs,according to the number of REs included in the E-CCE of the first typeand the E-CCE of the second type and a mapping method, multiplexing andmapping and feature processing in the time domain and frequency domain.

The transmitting unit 602 is configured to transmit an extended physicaldownlink control channel E-PDCCH to a user equipment, where the E-PDCCHis carried by the E-CCE.

Further, the transmitting unit 602 is specifically configured to notifyREs included in the E-CCE of the first type and/or REs included in theE-CCE of the second type to the user equipment through broadcast, systeminformation, or radio resource control protocol RRC signaling.

The above base station 60 corresponds to the above method embodiment.The base station 60 may be used in the steps of the above methodembodiment, and for its specific application in each step, reference maybe made to the above method embodiment, and will not be furtherdescribed herein.

In the methods for transmitting and receiving a control channel, thebase station, and the user equipment provided by the embodiments of thepresent invention, the base station determines, according to a systemconfiguration and/or user configuration, REs included in an E-CCE, andtransmits an E-PDCCH to the user equipment, where the E-PDCCH is carriedby the E-CCE; and the user equipment obtains, by using the same settingmethod as the base station, the REs included in the E-CCE, and receivesthe E-PDCCH over the REs included in the E-CCE. The E-CCE is set fixedlyand set dynamically or semi-statically, so that for available changingresources on the E-PDCCH carried by the E-CCE, a changing E-CCE iscorrespondingly available for transmission and reception, therebyimproving transmission efficiency, and reducing transmission complexity.

A user equipment 70 provided by an embodiment of the present invention,as shown in FIG. 9, includes a processing unit 701 and a receiving unit702.

The processing unit 701 is configured to obtain resource elements REsincluded in an extended control channel element E-CCE, where the REsincluded in the E-CCE are determined according to a system configurationand/or user configuration.

Further, as shown in FIG. 9, the processing unit 701 may include anobtaining module 7011 and a resource demapping module 7012.

The obtaining module 7011 is configured to obtain, according to resourceelements REs included in a resource set and REs of predeterminedoverheads in the resource set, resource elements REs included in anextended control channel element E-CCE; and specifically configured to:obtain, according to the number of REs included in a resource set andthe number of REs of predetermined overheads in the resource set, thenumber of available REs in the resource set; obtain, according to thenumber of available REs in the resource set and the number of REs ofpredetermined overheads in the resource set, the number of REs availablefor each E-CCE; and obtain, according to the number of REs available foreach E-CCE, the number of REs included in each E-CCE;

or specifically configured to: if the number of REs available for eachE-CCE is greater than a preset first threshold and smaller than a presetsecond threshold, obtain the number of REs available for each E-CCE asthe number of REs included in each E-CCE; if the number of REs availablefor each E-CCE is smaller than a preset first threshold, obtain thefirst threshold as the number of REs included in each E-CCE on aspecific resource; and/or if the number of REs available for each E-CCEis greater than a preset second threshold, obtain the second thresholdas the number of REs included in each E-CCE on a specific resource;

or specifically configured to: divide a resource set according to thepredetermined number of E-CCEs in the resource set to obtain resourcesubsets; obtain, according to the number of REs included in eachresource subset and the number of REs of predetermined overheads in eachresource subset, the number of available REs in each resource set; andobtain, according to the number of available REs in each resourcesubset, the number of REs included in each E-CCE in the resource set;

or configured to obtain, according to at least one of a preset precodingresource block group PRG, a resource block group RBG, a systembandwidth, a configured control channel bandwidth, different aggregationlevels, and different parameters of different E-CCEs at a sameaggregation level, the number of REs included in the E-CCE.

The resource demapping module 7012 is configured to: perform resourcedemapping, from a preset start point of the E-CCE, first in a frequencydomain and then in a time domain, or first in a time domain and then ina frequency domain, for the REs included in the E-CCE; if REs occupiedby the predetermined overheads exist during the resource demapping, skipRE positions occupied by the predetermined overheads and performresource demapping, where the number of demapped symbols is the numberof REs included in the E-CCE after the REs occupied by the predeterminedoverheads are correspondingly subtracted; or if REs occupied by thepredetermined overheads exist during the resource demapping, skip REpositions occupied by the predetermined overheads, where the number ofdemapped symbols is the number of REs included in the E-CCE.

It should be noted that the processing unit 701 is configured to processthe E-CCE, where the E-CCE includes an E-CCE of a first type and/or anE-CCE of a second type, where the number of REs included in the E-CCE ofthe first type is fixed on a first specific resource, and REs includedin the E-CCE of the second type change semi-statically or dynamically ona second specific resource.

The receiving unit 702 is configured to receive, over the REs includedin the E-CCE, an extended physical downlink control channel E-PDCCHtransmitted by a base station.

Further, the processing unit 701 is specifically configured to obtain,via the receiving unit 702 through broadcast, system information, orradio resource control protocol RRC signaling, REs included in the E-CCEof the first type and/or REs included in the E-CCE of the second typewhich are transmitted by the base station.

The above user equipment 70 corresponds to the above method embodiment.The user equipment 70 may be used in the steps of the above methodembodiment, and for its specific application in each step, reference maybe made to the above method embodiment, and will not be furtherdescribed herein.

In the methods for transmitting and receiving a control channel, thebase station, and the user equipment provided by the embodiments of thepresent invention, the base station determines, according to a systemconfiguration and/or user configuration, REs included in an E-CCE, andtransmits an E-PDCCH to the user equipment, where the E-PDCCH is carriedby the E-CCE; and the user equipment obtains, by using the same settingmethod as the base station, the REs included in the E-CCE, and receivesthe E-PDCCH over the REs included in the E-CCE. The E-CCE is set fixedlyand set dynamically or semi-statically, so that for available changingresources on the E-PDCCH carried by the E-CCE, a changing E-CCE iscorrespondingly available for transmission and reception, therebyimproving transmission efficiency, and reducing transmission complexity.

A person of ordinary skill in the art may understand that, all or a partof the steps of the foregoing method embodiments may be implemented by aprogram instructing relevant hardware. The foregoing programs may bestored in a computer readable storage medium. When the program runs, theforegoing steps included in the method embodiments are performed. Theforegoing storage medium includes various mediums capable of storingprogram codes, such as a ROM, a RPM, a magnetic disk or an optical disk.

The foregoing descriptions are merely specific embodiments of thepresent invention, but are not intended to limit the protection scope ofthe present invention. Any variation or replacement readily figured outby a person skilled in the art within the technical scope disclosed inthe present invention shall fall within the protection scope of thepresent invention. Therefore, the protection scope of the presentinvention shall be subject to the protection scope of the claims.

What is claimed is:
 1. A method for receiving a control channel, themethod comprising: determining, by a terminal device, a resource set andresource elements (REs) of predetermined overheads in the resource set,wherein the REs of the predetermined overheads comprise a RE of achannel state information-reference signal (CSI-RS), a RE of acell-specific reference signal (CRS), a RE of a demodulation referencesignal (DMRS), and a RE of a muted RE, and a RE of at least one of apaging channel and a synchronization channel; and receiving, by theterminal device from a base station, an extended physical downlinkcontrol channel (E-PDCCH) on REs comprised in an extended controlchannel element (E-CCE), wherein the E-CCE carries the E-PDCCH, the REscomprised in the E-CCE are a part of the REs in the resource set and donot contain the REs of the predetermined overheads.
 2. The methodaccording to claim 1, wherein the E-CCE is one of a first type E-CCE ora second type E-CCE, and the REs comprised in the E-CCE of the secondtype change semi-statically.
 3. The method according to claim 2,wherein: in a configured control channel region, E-CCEs of the secondtype have an equal spacing between search start points in a frequencydomain, wherein the spacing is at least one subcarrier.
 4. The methodaccording to claim 2, wherein a demodulation pilot (DMRS) antenna portof the E-CCE is dynamically changeable.
 5. The method according to claim1, further comprising: obtaining, by the terminal device according tothe number of the REs comprised in the resource set and the number ofREs of predetermined overheads in the resource set, the number ofavailable REs in the resource set; obtaining, by the terminal deviceaccording to the number of available REs in the resource set and thenumber of REs of predetermined overheads in the resource set, the numberof REs available for each E-CCE; and determining, by the terminal deviceaccording to the number of REs available for each E-CCE, the number ofREs comprised in each E-CCE, wherein: if the number of REs available foreach E-CCE is greater than a preset first threshold and smaller than apreset second threshold, the number of REs available for each E-CCEequals to the number of REs comprised in each E-CCE, or if the number ofREs available for each E-CCE is smaller than a preset first threshold,the number of REs comprised in each E-CCE on a specific resource equalsto the first threshold, or if the number of REs available for each E-CCEis greater than a preset second threshold, the number of REs comprisedin each E-CCE on a specific resource equals to the second threshold. 6.The method according to claim 1, wherein the resource set is determinedaccording to at least one of a preset precoding resource block group(PRG), a resource block group (RBG), a system bandwidth, a configuredcontrol channel bandwidth, different aggregation levels, and differentparameters of different E-CCEs at a same aggregation level.
 7. Themethod according to claim 1, wherein the resource set comprises at leastone of a physical resource block (PRB), a physical resource block pair,a precoding resource block group (PRG), a resource block group (RBG),and a set divided into various E-CCE resources.
 8. A terminal device,comprising: a processor; and a receiver communicatively connected withthe processor, wherein the processor is configured to: determine aresource set and resource elements (REs) of predetermined overheads inthe resource set, wherein the REs of the predetermined overheadscomprise a RE of a channel state information-reference signal (CSI-RS),a RE of a cell-specific reference signal (CRS), a RE of a demodulationreference signal (DMRS), and a RE of a muted RE, and a RE of at leastone of a paging channel and a synchronization channel, and detect anextended physical downlink control channel (E-PDCCH) on REs comprised inan extended control channel element (E-CCE), wherein the E-CCE carriesthe E-PDCCH that is received by the receiver, the REs comprised in theE-CCE are a part of the REs in the resource set and do not contain theREs of the predetermined overheads.
 9. The terminal device according toclaim 8, wherein the E-CCE is one of a first type E-CCE or a second typeE-CCE, and the REs comprised in the E-CCE of the second type changesemi-statically.
 10. The terminal device according to claim 9, wherein:in a configured control channel region, E-CCEs of the second type havean equal spacing between search start points in a frequency domain,wherein the spacing is at least one subcarrier.
 11. The terminal deviceaccording to claim 9, wherein a demodulation pilot (DMRS) antenna portof the E-CCE is dynamically changeable.
 12. The terminal deviceaccording to claim 8, wherein the processor is further configured to:obtain, according to the number of the REs comprised in the resource setand the number of REs of predetermined overheads in the resource set,the number of available REs in the resource set; obtain, according tothe number of available REs in the resource set and the number of REs ofpredetermined overheads in the resource set, the number of REs availablefor each E-CCE; and determine, according to the number of REs availablefor each E-CCE, the number of REs comprised in each E-CCE, wherein: ifthe number of REs available for each E-CCE is greater than a presetfirst threshold and smaller than a preset second threshold, the numberof REs available for each E-CCE equals to the number of REs comprised ineach E-CCE, or if the number of REs available for each E-CCE is smallerthan a preset first threshold, the number of REs comprised in each E-CCEon a specific resource equals to the first threshold, or if the numberof REs available for each E-CCE is greater than a preset secondthreshold, the number of REs comprised in each E-CCE on a specificresource equals to the second threshold.
 13. The terminal deviceaccording to claim 8, wherein the resource set is determined accordingto at least one of a preset precoding resource block group (PRG), aresource block group (RBG), a system bandwidth, a configured controlchannel bandwidth, different aggregation levels, and differentparameters of different E-CCEs at a same aggregation level.
 14. Theterminal device according to claim 8, wherein the resource set comprisesat least one of a physical resource block (PRB), a physical resourceblock pair, a precoding resource block group (PRG), a resource blockgroup (RBG), and a set divided into various E-CCE resources.
 15. Anapparatus comprising: a storage medium including executableinstructions; and a processor, wherein the executable instructions, whenexecuted by the processor, cause the apparatus to: determine a resourceset and resource elements (REs) of predetermined overheads in theresource set, wherein the REs of the predetermined overheads comprise aRE of a channel state information-reference signal (CSI-RS), a RE of acell-specific reference signal (CRS), a RE of a demodulation referencesignal (DMRS), and a RE of a muted RE, and a RE of at least one of apaging channel and a synchronization channel; and detect an extendedphysical downlink control channel (E-PDCCH) on REs comprised in anextended control channel element (E-CCE) wherein the E-CCE carries theE-PDCCH, and the REs comprised in the E-CCE are a part of the REs in theresource set and do not contain the REs of the predetermined overheads.16. The apparatus according to claim 15, wherein the E-CCE is one of afirst type E-CCE or a second type E-CCE, and the REs comprised in theE-CCE of the second type change semi-statically.
 17. The apparatusaccording to claim 16, wherein: in a configured control channel region,E-CCEs of the second type have an equal spacing between search startpoints in a frequency domain, wherein the spacing is at least onesubcarrier.
 18. The apparatus according to claim 16, wherein ademodulation pilot (DMRS) antenna port of the E-CCE is dynamicallychangeable.
 19. The apparatus according to claim 15, wherein theexecutable instructions, when executed by the processor, further causethe apparatus to: obtain, according to the number of the REs comprisedin the resource set and the number of REs of predetermined overheads inthe resource set, the number of available REs in the resource set;obtain, according to the number of available REs in the resource set andthe number of REs of predetermined overheads in the resource set, thenumber of REs available for each E-CCE; and determine, according to thenumber of REs available for each E-CCE, the number of REs comprised ineach E-CCE, wherein: if the number of REs available for each E-CCE isgreater than a preset first threshold and smaller than a preset secondthreshold, the number of REs available for each E-CCE equals to thenumber of REs comprised in each E-CCE, or if the number of REs availablefor each E-CCE is smaller than a preset first threshold, the number ofREs comprised in each E-CCE on a specific resource equals to the firstthreshold, or if the number of REs available for each E-CCE is greaterthan a preset second threshold, the number of REs comprised in eachE-CCE on a specific resource equals to the second threshold.
 20. Theapparatus according to claim 15, wherein the resource set is any one ofa physical resource block (PRE), a physical resource block pair, aprecoding resource block group (PRG), a resource block group (REG), anda set divided into various E-CCE resources.